Google Docs has a new Research tool, making it easy to add information from the web to your documents. To access the tool:

Select the Research option from the Tools menu.
Use the keyboard shortcut (Cmd + Opt + R on Mac, Ctrl + Alt + R on PC).
Right-click on a specific word and select Research.

The Research tool will appear along the right-hand side of your document. You can start a search by typing into the search bar. You can narrow your search to specific types of results (e.g. images, quotations) by using the drop-down menu in the search bar.

More info: https://support.google.com/docs/bin/answer.py?hl=en&answer=2481802&p=documents_research

Using Google Research tool : http://www.macworld.com/article/1166832/hands_on_with_google_docss_new_research_tool.html